"We're aware of this issue and will be speaking to Facebook, as well as liaising with the Irish data protection authority, to learn more about the circumstances," a spokesman for the Information Commissioner's Office (ICO) said in a statement.

At issue is a one-week experiment that Facebook conducted in 2012 whereby it served up largely negative or largely positive posts to users' news feeds to see if it would affect their mood and their own posts. Not surprisingly, seeing a multitude of negative posts prompted Facebook users to post negative comments themselves, while happy posts prompted cheerful updates.

This "emotional contagion" study involved about 700,000 users, who were not informed of the experiment beforehand. The results were made public when a report from Facebook data scientist Adam Kramer, co-authored by Cornell's Jeff Hancock and Jamie Guillory, was published recently in the journal Proceedings of the National Academy of Scientists.

The news prompted concern about Facebook manipulating its users' emotions. Forbes also reported that Facebook changed its terms of service to allow it to use users' data for "research" - but it did so several months after the Facebook experiment took place.

In a Sunday blog post, Kramer said "the reason we did this research is because we care about the emotional impact of Facebook and the people that use our product."

Still, "I can understand why some people have concerns about it, and my coauthors and I are very sorry for the way the paper described the research and any anxiety it caused," he wrote. "In hindsight, the research benefits of the paper may not have justified all of this anxiety."

Cornell, meanwhile, issued its own statement to stress that Hancock and Guillory did not participate in any data collection, but only analyzed the results. "Their work was limited to initial discussions, analyzing the research results and working with colleagues from Facebook to prepare the peer-reviewed paper," the schools said.

Chloe Albanesius has been with PCMag.com since April 2007, most recently as Executive Editor for News and Features. Prior to that, she worked for a year covering financial IT on Wall Street for Incisive Media. From 2002 to 2005, Chloe covered technology policy for The National Journal's Technology Daily in Washington, DC. She has held internships at NBC's Meet the Press, washingtonpost.com, the Tate Gallery press office in London, Roll Call, and Congressional Quarterly. She graduated with a bachelor's degree in journalism from American University...
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